So I took my car to the shop as my overflow container for my radiator was empty. I saw there was marks of it leaking out. They replaced the upper radiator hose but tell me my problem isn't solved. They are telling me I have another leak on the back side of the engine by the turbo. I have been quoted $1200 for installation and parts. They said it's a kit of fittings for the oil cooler. Any one else had this? They said that GMC coolant gets very acidic and it should be changed frequently.